Based on feedback received from one of Australian users I checked and found discrepancy between what is displayed on Yahoo Finance
and what is downloaded when you click on "Download data" link on the very same page.
As you can see when you click on "Download data" link (that is what AmiQuote uses to download data), you get correct OHLC V data but the date is incorrect (one day back, Sunday instead of Monday).
The only thing you can do at the moment is to complain directly to Yahoo that the 'Download link' data do not match the data displayed on the very same page.
I was thinking about implementing timeshift for .AX symbols (via ASCII importer's
$TIMESHIFT 24 command) to correct this but trouble is that for some date ranges their data is correct (Monday-Friday) but other date ranges have -1 day shift (so they are Sunday-Thursday). For example data between October 2nd, 2016 and April 3rd 2017 are incorrect (dates shifted one day back). Dates from April 3rd, 2017 till now (June 6, 2017) are correct.
It seems that Yahoo has some trouble with the timestamping because Australia is in different timezone so for clueless US company like Yahoo it may look like "previous day" sometimes. If that was constant timeshift, we could adjust that, but with current, random behavior it is really messy.